(1) Field of the Invention
The present invention relates to an image processing device, and more particularly, to an image processing device for processing an image signal in real time for the detection of an object and for image recognition.
(2) Description of the Related Art
Image recognition technique is a technique for detecting the presence of an object based on an image acquired by a CCD camera or the like and analyzing the contents of the image.
In ITS (Intelligent Transport System: expressway traffic system), image recognition technique is used, for example, to detect a stopping vehicle or a fallen object on the road.
Also, image recognition technique is used in a wide field to detect a trouble in electric power facilities, such as a short circuit or a ground fault, a fire in a refuse incineration equipment, etc.
Meanwhile, algorithms for image recognition include, for example, background differentiation whereby an object is detected based on a difference between a background image stored beforehand and each of images input at regular intervals of time, and feature extraction whereby an object is detected by extracting feature items from images, among a diversity of other algorithms.
According to image recognition techniques in general, where the algorithms are large in content, a single image processor is unable to execute the required process, and therefore, frames are thinned out and then subjected to pipeline control to thereby increase the processing speed.
Also, to increase the processing speed, the processor performs concurrent parallel processing for the input/output of image data and for image recognition. According to image processing algorithms, moreover, an image is divided into a plurality of parts which are then usually subjected to distributed processing.
In the conventional pipeline control as described above, however, a plurality of processors successively provide their results of processing with respective time lags before unprocessed data is finally converted to processed data, thus entailing a delay time.
Such a delay time increases in proportion to the number of connection stages of processors and thus poses a problem in cases where a rapid event is to be detected based on an image moving at high speed.
For example, in the case of driverless automatic drive which is under development according to ITS, a fallen object or an abnormal situation must be detected immediately after the occurrence of such an event, in order to prevent an accident. Thus, in image recognition applied to automobiles, high-speed detection is essential.
Also, in the conventional parallel processing for image data, a single bus system is employed and the data input/output process and the image recognition process are carried out through the single bus. Consequently, conflict frequently occurs on the bus, giving rise to a problem that the quality and reliability of the system lower.
Further, in the conventional algorithm distributed processing, a serial communication port with low data transfer capacity is used for synthesizing images after the distributed processing, and accordingly, the synthesis cannot be performed on a real-time basis ({fraction (1/30)} second), thus impeding high-speed detection.
An object of the present invention is to provide an image processing device which is improved in the image processing speed and capable of detecting an object at high speed.
To achieve the above object, there is provided an image processing device for processing an image signal in real time. The image processing device comprises line interval expanding means for expanding an interval between lines of the image signal by an amount corresponding to a number of frames which have been thinned out for real-time processing during frame processing of the image signal, and a plurality of image processing means for performing line processing of the lines of which the interval has been expanded, according to pipeline control.